A wake-up lamp is a lamp comprising one or more light sources, of which the power (corresponding to light intensity) is slowly and gradually increased from zero (or a starting value close to zero) to a maximum value during a certain time period, for instance 30 minutes, and after that the power is maintained. Such a lamp is used to simulate the natural process of increasing daylight level at sunrise, which has a positive effect on people waking up. The process can also be run in reverse, so that the power (corresponding to light intensity) is slowly and gradually decreased from the maximum value to zero (or an end value close to zero), to simulate the natural process of decreasing daylight level at sunset, which has a positive effect on people going to sleep.
Wake-up lamps and fall-asleep lamps are commonly known, so a more detailed explanation is omitted here. Further, for sake of convenience, the following explanation will focus on wake-up lamps but the same explanation applies, mutatis mutandis, to fall-asleep lamps, as should be clear to a person skilled in the art.
Wake-up lamps can be implemented with different types of light sources. For instance, the light source used can be an incandescent lamp, a discharge lamp, an LED, etc. Varying the output power of a light source is typically done by varying the lamp current.